Muffle-furnace for assaying and annealing



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J. HOSKINS.

MUFFL'E FURNACE FOR ASSAYING AND ANNEALING.

No. 315,036; Patented Apr. 7. 1885.

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. J. HOSKINS. MUPFLE FURNACE FOR ASSAYING AND ANNEALING.

No. 315,036. Patented Apr. 7, 1885.

UNITED STATES PATENT OFFICE.

JOHN HOSKINS, OF CHICAGO, ILLINOIS.

MUFFLE-FURNACE FOR ASZSAYING AND ANNEALING.

'fiPE-CIPICATION forming part of Letters Patent No. 315,036, dated April 7, 1885. Application filed June-28, 1884. (No model) I 0 all whom it may concern.-

Be it known that I, J OHN HosKINs, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and Improved Muffle-Furnace for Assayiug and Annealing; and I hereby declare the following to be a full, clear, and exact description of the same.

My invention relates to a furnace to be heated by gaseous fuel or liquid fuel reduced entirely or almost entirely to a gaseous state and introduced into the combustion-chamber, and preferably by means of the hydrocarbongas burner shown, described, and claimed in Letters Patent of the United States No. 267 ,431, granted to me November 14, 1882. i

It is the object of my invention to provide a furnace in which complete or almost complete combustion of the fuel employed shall take place within the combustion-chamber, whereby practically only the heated products of combustion and heat shall enter the oven or mufflechamber and heat uniformly throughout its whole extent the receptacle contained therein for the substances to be acted upon; and it is my object, further, to provide a furbase that may be used to great advantage for purposes of annealing and enameling by jewelers and dentists, and others who practice such arts.

To these ends my invention consists in a furnace having a combustion-chamber in immediate communication with the oven or muflie-chamber, and inclosed excepting as to the opening which leads to it,and as to such communication.

My invention also consists in providing one or more ovens to rest upon the first oven, and having means of communication with the first oven, whereby the heat and products of combustion may be distributed equally about all parts of the several muffies so superimposed in series; and my invent-ion consists,further,in certain details of construction and combinations of parts, all as hereinafter more fully set forth.

In the drawings, Figure 1 is a perspective view of my improved furnace, showing the position of the muffle within the furnace proper or muffle-chamber, and the opening in the I upper side of the latter forming the outlet for end elevation showing the communication of the zombustionehamber with the muffie-chamber containing a muffle, and showing the said mufiie-chamber communicating with a second muffle-chamber, represented in broken lines above the first, and likewise containing a muffle, also represented in broken lines; and Fig. 3, a side elevation in section, showing partly in broken lines the construction and relative positions of the combustion-chamber and ovens containing muflies.

A is a muffle-furnace composed of fire-clay or other refractory or incombustible material,

tion, in two parts, A and A, which are secured together by means of metal strips t, bent to a trough shape and caused to inclose the corners. A metallic strap, 3, is passed horizontally around the upper marginof the part A to contribute additional firmness to the same, and is riveted at each side of a corner to the material forming the part A the rivets passing at the same time through the vertical corner-braces t, to secure the latter at their upper ends. Asimilarstrap, s, is caused to surround the lower side of the part A, for the same purpose that the strip 8 is provided upon the-part A The part A rests upon legs 0, riveted toward their upper ends to both sides of each lower corner of the same, the rivets entering into the substance composing the part A, and passing through the lower portions of the corner-braces t, to fasten the latter at their lower extremities, and through the strip 8, to secure it in position.

part A, and comprising, preferably, an in-l wardly-tapering circular opening, which extends to the wall q.

O is a longitudinal slot formed in the upper side of the combustion-chamber to afford communication between the latter and the mufflechamber D. The opening leading from the combustion to the muffle chamber may be of any desired form other than the slot 0, comprising, for example, perforations through the upper wall of the part A, or an opening of greater width than that of the slot 0, but of the products of combustion; Fig. 2, a sectional and formed, for convenience of construe- Bis a combustion-chamber formed in the ICO equal or approximately equal length, the purpose being to produce contact of the products of combustion from the chamber B with all parts of the muffle in the muffle-chamber simultaneously, while preventing, owing to the substantially complete combustion which takes place within the chamber B, particularly after the latter shall have once become heated, the

entrance of flame into the muffle-chamber."

side with an opening, 0, similar to the opening 0, or to either of the modifications of the latter hereinbefore mentioned, to form an outlet for'the products of combustion, or to provide communication with another mufflechamber, D, containing a muffle, E, and having an opening to correspond with the opening 0' upon the same.

Any desired number of muffle chambers communicable with each other, and corresponding with the part A may be provided to lie one upon the other, when the heat supplied to each from the one combustion-chamber will diminish in degree as it rises, producing a lower temperature in the top chamber than in the one immediately below it, and so on down, owing to which the various muffle-chambers may be used for carrying out different processes, or the different steps of the same process demanding varying degrees of heat.

To operate my device flame is blown into the combustion-chamber B by means of my hydrocarbon apparatus hereinbefore referred to, which is adjusted to varying distances from the mouth of the combustion-chamber, depending upon the size of such apparatus and of the furnace, to permit mixture with the flame of air, whereby combustion shall take place to a very great extent before the entrance of flame into the combustion-chamber. The tapering form of the combustion-chamber effects equalization of the discharge of the products-of combustion through the slot in the top of the chamber B, and thereby causes, as it is found, the maximum of heat to be utilized, and as the products of combustion enter the mufflechamber and completely surround the muffle therein the latter is heated equally throughout its whole extent.

When more than one muffle-chamber is used, the combustion occurring within the combustion-chamber will always, other things being equal, produce the same variation in degree of the heat from one chamber to the other.

My furnace may of course be employed for purposes other than assaying, annealing, enameling, and the like, and it may of course be formed in any size necessary to render it suitable for the purpose for which it is employed.

What I claim as new, and desire to secure by Letters Patent, is

1. In a furnace for burning gaseous or liquid fuel, the combination ofa muffle-chamber, D, having an opening, 0, and a combustionchamber, B, provided with an opening leading into it and with a passage, 0, connecting it with the muffle-chamber, and wholly and permanently inclosed elsewhere, substantially as described, and for the purpose set forth.

2. In a furnace, the'combination of an inwardly-tapering combustiolrchamber, B,oven

or muffle-chamber D, having an opening, 0,

and passage 0, connecting the muffle-chamber a JOHN HosKms.

and combustion-chamber, substantially as de- In presence of- THOMAS A. BANNING, WM. I. BUNKER. 

